<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="bootstrap/css/bootstrap.min.css">
    <title>Document</title>
    <style>
        [class^=col-md] {
            background-color: aquamarine;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="row">
            <!-- 改变列的排列顺序 把右边的格子排在左边 左边格子排在右边 -->
            <div class="col-md-4 col-md-push-8">左</div>
            <div class="col-md-8 col-md-pull-4">右</div>
        </div>
    </div>
</body>

</html>